package br.com.vagner.sunshine.app;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class ForecastFragment extends Fragment {

	private final String LOG_TAG = ForecastFragment.class.getSimpleName();
	
	private ArrayAdapter<String> mForecastAdapter;

	public ForecastFragment() {

	}
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setHasOptionsMenu(true);
	}
	
	@Override
	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
		inflater.inflate(R.menu.forecastfragment, menu);
	}
	
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		int id = item.getItemId();
		if (id == R.id.action_refresh) {
			this.updateWeather();
			return true;
		}
		
		return super.onOptionsItemSelected(item);
	}

	private void updateWeather() {
		SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(getActivity());
		String location = sharedPref.getString(getString(R.string.pref_location_key),
				getString(R.string.pref_location_default));
		
		FetchWeatherTask weatherTask = new FetchWeatherTask();
		weatherTask.execute(location);
	}
	
	@Override
	public void onStart() {
		super.onStart();
		this.updateWeather();
	}

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {

		View rootView = inflater.inflate(R.layout.fragment_main, container,
				false);

		// Now that we have some dummy forecast data, create an
		// ArrayAdapter.
		// The ArrayAdapter will take data from a source (like our dummy
		// forecast) and
		// use it to populate the ListView it's attached to.
		this.mForecastAdapter = new ArrayAdapter<String>(
				getActivity(), // The current context (this activity)
				R.layout.list_item_forecast, // The name of the layout ID.
				R.id.list_item_forecast_textview, // The ID of the textview to populate.
				new ArrayList<String>());

		ListView listView = (ListView) rootView.findViewById(R.id.listview_forecast);
		listView.setAdapter(mForecastAdapter);
		listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				
				Intent intent = new Intent(getActivity(), DetailActivity.class)
						.putExtra(Intent.EXTRA_TEXT, mForecastAdapter.getItem(position));
				startActivity(intent);
			}
		});

		return rootView;
	}

	public class FetchWeatherTask extends AsyncTask<String, Void, String[]> {

		@Override
		protected String[] doInBackground(String... params) {
			
			if (params.length == 0) {
				return null;
			}
			
			// These two need to be declared outside the try/catch
			// so that they can be closed in the finally block.
			HttpURLConnection urlConnection = null;
			BufferedReader reader = null;

			// Will contain the raw JSON response as a string.
			String forecastJsonStr = null;
			
			String format = "json";
			String units = "metric";
			int numDays = 7;

			try {
				final String FORECAST_BASE_URL = "http://api.openweathermap.org/data/2.5/forecast/daily?";
				final String QUERY_PARAM = "q";
				final String FORMAT_PARAM = "mode";
				final String UNITS_PARAM = "units";
				final String DAYS_PARAM = "cnt";
				
				Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon()
						.appendQueryParameter(QUERY_PARAM, params[0])
						.appendQueryParameter(FORMAT_PARAM, format)
						.appendQueryParameter(UNITS_PARAM, units)
						.appendQueryParameter(DAYS_PARAM, Integer.toString(numDays))
						.build();
				
				URL url = new URL(builtUri.toString());
				
				// Create the request to OpenWeatherMap, and open the connection
				urlConnection = (HttpURLConnection) url.openConnection();
				urlConnection.setRequestMethod("GET");
				urlConnection.connect();

				// Read the input stream into a String
				InputStream inputStream = urlConnection.getInputStream();
				StringBuffer buffer = new StringBuffer();
				if (inputStream == null) {
					// Nothing to do.
					return null;
				}
				reader = new BufferedReader(new InputStreamReader(inputStream));

				String line;
				while ((line = reader.readLine()) != null) {
					// Since it's JSON, adding a newline isn't necessary (it
					// won't affect parsing)
					// But it does make debugging a *lot* easier if you print
					// out the completed
					// buffer for debugging.
					buffer.append(line + "\n");
				}

				if (buffer.length() == 0) {
					// Stream was empty. No point in parsing.
					return null;
				}
				
				forecastJsonStr = buffer.toString();
				
			} catch (IOException e) {
				Log.e(LOG_TAG, "Error ", e);
				// If the code didn't successfully get the weather data, there's
				// no point in attemping
				// to parse it.
				return null;
			} finally {
				if (urlConnection != null) {
					urlConnection.disconnect();
				}
				if (reader != null) {
					try {
						reader.close();
					} catch (final IOException e) {
						Log.e(LOG_TAG, "Error closing stream", e);
					}
				}
			}
			
			try {
				return getWeatherDataFromJson(forecastJsonStr, numDays);
			} catch (JSONException e) {
				Log.e(LOG_TAG, e.getMessage(), e);
				e.printStackTrace();
			}
			
			return null;
		}
		
		@Override
		protected void onPostExecute(String[] result) {
			if (result != null) {
				mForecastAdapter.clear();
				for (String dayForecastStr : result) {
					mForecastAdapter.add(dayForecastStr);
				}
			}
		}
	}
	
	/*
	 * The date/time conversion code is going to be moved outside the asynctask
	 * later, so for convenience we're breaking it out into its own method now.
	 */
	private String getReadableDateString(long time) {
		// Because the API returns a unix timestamp (measured in seconds),
		// it must be converted to milliseconds in order to be converted to
		// valid date.
		Date date = new Date(time * 1000);
		SimpleDateFormat format = new SimpleDateFormat("E, MMM d");
		return format.format(date).toString();
	}

	/**
	 * Prepare the weather high/lows for presentation.
	 */
	private String formatHighLows(double high, double low) {
		// For presentation, assume the user doesn't care about tenths of a
		// degree.
		long roundedHigh = Math.round(high);
		long roundedLow = Math.round(low);

		String highLowStr = roundedHigh + "/" + roundedLow;
		return highLowStr;
	}

	/**
	 * Take the String representing the complete forecast in JSON Format and
	 * pull out the data we need to construct the Strings needed for the
	 * wireframes.
	 * 
	 * Fortunately parsing is easy: constructor takes the JSON string and
	 * converts it into an Object hierarchy for us.
	 */
	private String[] getWeatherDataFromJson(String forecastJsonStr, int numDays)
			throws JSONException {
		
		// These are the names of the JSON objects that need to be extracted.
		final String OWM_LIST = "list";
		final String OWM_WEATHER = "weather";
		final String OWM_TEMPERATURE = "temp";
		final String OWM_MAX = "max";
		final String OWM_MIN = "min";
		final String OWM_DATETIME = "dt";
		final String OWM_DESCRIPTION = "main";

		JSONObject forecastJson = new JSONObject(forecastJsonStr);
		JSONArray weatherArray = forecastJson.getJSONArray(OWM_LIST);

		String[] resultStrs = new String[numDays];
		for (int i = 0; i < weatherArray.length(); i++) {
			// For now, using the format "Day, description, hi/low"
			String day;
			String description;
			String highAndLow;

			// Get the JSON object representing the day
			JSONObject dayForecast = weatherArray.getJSONObject(i);

			// The date/time is returned as a long. We need to convert that
			// into something human-readable, since most people won't read
			// "1400356800" as
			// "this saturday".
			long dateTime = dayForecast.getLong(OWM_DATETIME);
			day = getReadableDateString(dateTime);

			// description is in a child array called "weather", which is 1
			// element long.
			JSONObject weatherObject = dayForecast.getJSONArray(OWM_WEATHER)
					.getJSONObject(0);
			description = weatherObject.getString(OWM_DESCRIPTION);

			// Temperatures are in a child object called "temp". Try not to name
			// variables
			// "temp" when working with temperature. It confuses everybody.
			JSONObject temperatureObject = dayForecast
					.getJSONObject(OWM_TEMPERATURE);
			double high = temperatureObject.getDouble(OWM_MAX);
			double low = temperatureObject.getDouble(OWM_MIN);

			highAndLow = formatHighLows(high, low);
			resultStrs[i] = day + " - " + description + " - " + highAndLow;
		}
		
		return resultStrs;
	}

}
